A casement window generally includes a frame portion, which is mounted in a rough opening provided in a structure, and an operable sash portion mounted in the frame with one or more hinges. A typical casement window hinge includes a track portion, which attaches to the window frame, and a sash arm, which attaches to the window sash. One end of the sash arm is pivotally attached to a shoe that is slidable on the track. A link arm is pivotally attached to each of the track and the sash arm. In operation, as the sash swings from the closed position to the open position, the sliding shoe slides along the track so that the inward side of the sash moves away from the corresponding side of the frame. Various prior casement window hinges are described and depicted in U.S. Pat. Nos. 1,706,830; 1,711,927; 2,094,990; 2,383,395; 3,797,169; 4,726,092; 5,040,267; 5,152,102; 5,491,930; 6,112,371; 6,134,751; and 6,643,896, all of which are hereby fully incorporated herein by reference.
A small degree of misalignment of the sash in the window frame may cause leaks and interference between the sash and frame during operation of the window. Consequently, a relatively high degree of accuracy and precision is required during window manufacture to ensure proper positioning and attachment of the sash arm to the sash. Fastener holes are generally pre-drilled in the sash using a jig in order to achieve the desired accuracy, thereby adding steps and attendant manufacturing costs. What is needed in the industry is a casement window hinge that is repeatably accurately attachable to a sash without pre-drilling or attachment jigs.